Preservatives for surface-coating compositions

ABSTRACT

WHEREIN X represents hydrogen, lower alkyl, -CH2OH, or -SCH2OH; Y represents nitro or halogen; and n represents a number in the range of 0 to 2 are used to protect surface-coating compositions from deterioration resulting from attack by fungi and bacteria. Among the most effective of these compounds as a biocide is 1hydroxymethyl-2-methylbenzimidazole.   Compounds that have the structural formula

United States Patent 11 1 Minierl 1 Dec. 30, 1975 [54] PRESERVATIVES FOR SURFACE-COATING COMPOSITIONS [75] Inventor: Pasquale P. Minieri, Woodside,

{73] Assignee: Tenneco Chemicals, Inc., Saddle Brook, NJ.

[22] Filed: Mar. 6, I974 21 Appl. No.: 448,734

[51] Int. Cl. C09D 5/14 [58] Field of Search 106/15 AF; 260/29.6 MN,

260/458 N, 29.6 MQ, 309.2, 45.95 P; 424/273 [56] References Cited UNITED STATES PATENTS 2,933,504 4/1960 Klopping 106/15 3,147,274 9/1964 Moyle et 106/15 3,662,069 5/1972 Dittmar 106/15 3,779,973 12/1973 Minieri 260/29.6 MN

3,814,714 6/1974 Minieri 260/29.6 3,816,447 6/1974 Minieri 260/296 MN 3,817,761 6/1974 Brake 1 106/15 3,821,393 6/1974 Janiak et a1... 260/3092 3,826,657 7/1974 Minieri 260/296 3,845,212 10/1974 Yovich et a1. 106/15 AF FOREIGN PATENTS OR APPLICATIONS 1,450,541 7/1966 France 260/3092 1,472,978 2/1967 France 260/3092 Primary Examiner-Eugene C. Rzucidlo Attorney, Agent, or FirmEvelyn Berlow [57] ABSTRACT Compounds that have the structural formula cn ou wherein X represents hydrogen, lower alkyl, CH- ,OI-I, or -SCI-1,0H; Y represents nitro or halogen; and n represents a number in the range of 0 to 2 are used to protect surface-coating compositions from deterioration resulting from attack by fungi and bacteria. Among the most effective of these compounds as a biocide is 1-hydroxymethyl-2-methylbenzimidazole.

12 Claims, No Drawings PRESE RV ATIV ES FOR SURFACE-COATING COMPOSITIONS This invention relates to surface-coating compositions that have improved resistance to deterioration resulting from attack by fungi, bacteria. and other microorganisms. More particularly, it relates to surfacecoating compositions that contain biocidal amounts of N-hydroxymethylbenzimidazoles.

It is well known in the art that paints and varnishes often have inadequate resistance to the action of microorganisms. Some of these coating compositions, such as enamels and house paints, contain as their resinous hinders drying oils, oleoresinous varnishes, or alkyd resins. which are subject to attack by fungi and bacteria. Others, for example, aqueous dispersions of waterinsoluble synthetic linear polymers, generally contain as plasticizers and thickeners materials that have their origin in animal or vegetable sources and that render the compositions susceptible to mildew. The resulting deterioration of the surface-coating compositions seriously hinders their full scale utilization, particularly in those areas and in those applications that are conducive to such attack.

Various hiocidal materials have been suggested for use in surface-coating compositions, but none has proven entirely satisfactory in this application. Some do not provide the required prolonged protection against attack by microorganisms, while others undergo sulfide staining and still others hydrolyze in alkaline aqueous paint systems or separate from the applied coating by migration, volatilization, or leaching once the coating has been spread in a thin layer over the surface to be protected.

This invention relates to biocides that are of particular value in surface-coating compositions. These biocides, which are thoroughly compatible with the resinous binders that commonly are used in surface-coating compositions and which are resistant to sulfide staining, provide excellent and prolonged resistance to deterioration resulting from attack by fungi and other microorganisms without adversely affecting the color, pH, viscosity, and other physical properties of the surfacecoating compositions.

The biocidal compounds that are used in the surfacecoating compositions of this invention are N-hydroxymethylhenzimidazoles. These compounds have the structural formula N n c-x i cn on l-hydroxymethyl-o-chlorobenzimidazole, l-hydroxymethyl-Z-methyl-S-chlorobenzimidazole, l-hydroxymethyl 5,7-dichlorobenzimidazole, l-hydroxymethyl- 2-propyl-5,o-dinitrobenzimidazole, l ,2-bis( hydroxymethyl )benzimidazole, l,2-bis( hydroxymethyl )-5- bromobenzimidazole, l-hydroxymethyl-2-hydroxymethylthiobenzimidazole, l-hydroxymethyl-Z-hydroxymethylthio-S ,6'dibromobenzimidazole, l-hydroxymethyl-Z-ethyl-b-iodobenzimidazole, l-hydroxymethyl-2-butyl-5-fluoro-benzimidazole, and the like.

The biocidal compounds of this invention may be prepared by any suitable and convenient procedure. They can, for example, be prepared by the reaction of the appropriate benzimidazole or substituted benzimidazole with paraformaldehyde. The reaction, is usually carried out in a solvent, such as methanol or isopropanol, at the reflux temperature of the reaction mixture.

The l-hydroxymethylbenzimidazoles of this invention can be used to impart fungal and bacterial resis tance to a wide variety of surface-coating compositions including both organic solvent-based and water-based coating systems.

In a preferred embodiment of the invention. the lhydroxy-methylbenzimidazoles are used as the biocide in aqueous surface-coating compositions that contain about 10 percent to percent by weight of a waterinsoluble, film-forming, resinous binder that is an oleoresinous binder, a synthetic linear additon binder, or a mixture of these binders. Suitable oleoresinous binders include drying oils, such as linseed oil, tung oil, soybean oil, dehydrated castor oil, safflower oil, or fish oil; bodied drying oils; blends of drying oils or bodied drying oils with a resin component, such as limed rosin, an ester gum, or a phenolic resin; oleoresinous varnishes formed by heating one of the aforementioned resins with one or more drying oils or bodied drying oils; and alkyd resins, which are resinous products resulting from the reaction of a polyhydric alcohol, such as pentaerythritol or glycerol, with a dicarboxylic acid, such as phthalic anhydride, and fatty acids. The useful aqueous dispersions of synthetic linear addition polymers are ordinarily prepared by the emulsion polymerization of ethylenically unsaturated compounds, especially those of monoethylenically unsaturated character, al though butadiene, chlorobutadiene, and isoprene may be used to some extent. Illustrative of the synthetic linear addition polymers that can be used as the resinous binder in the aqueous dispersions are polyvinyl acetate; polyvinyl butyrate; polyvinyl chloride; copolymers of vinyl acetate with vinyl chloride; copolymers of vinyl acetate with acrylonitrile; copolymers of vinyl chloride with acrylonitrile; copolymers of vinyl chloride with vinylidene chloride; polyethylene; polyisohutylene; polystyrene; copolymers of styrene with butadicne; copolymers of acrylonitrile with butadiene; copolymers of methyacrylic acids esters of alcohols having 1 to 8 carbon atoms with vinyl acetate, vinyl chloride, acrylonitrile, or styrene; copolymers of acrylic acid esters of alcohols having I to 8 carbon atoms with vinyl acetate, vinyl chloride, acrylonitrile, or styrene; copolymers of the aforementioned acrylic acid esters. the aforementioned methacrylic acid esters, and acrylic acid; and copolymers of styrene with maleic anhydride.

The l-hydroxymethylbenzimidazoles can also be used as the biocide in organic solvent-based systems that contain an oleoresinous binder as hereinbefore defined.

Only a small amount of the l-hydroxymethylbenzimidazole is required to protect the surface-coating composition from attack by fungi and bacteria. As little as 0.107: of one or more of these compounds, based on the weight of the composition, will bring about an appreciable improvement in the resistance of the compo sition to attack by microorganisms. Three percent or more otthe biocidal compounds can be used, but these larger amounts generally do not provide further improvement in the properties of the surface-coating compositions and for this reason are not ordinarily used. The amount of the biocidal compound that will provide optimum protection for a surface-coating composition depends upon such factors as the choice of biocidal compound, the choice of resinous binder and other components of the surface-coating composition and the amount of each that is used, and the application for which the coating composition is intended. in most cases about 1 percent to 2 percent of the lhydroxymethylbenzimidazoles. based on the weight of the surface-coating composition, is used to protect the composition from attack by fungi, and 0.2 percent to 0.6 percent of the l-hydroxymethylbenzimidazoles, based on the weight of the composition, is used to protect aqueous surface-coating compositions from attack by bacteria.

In addition to the resinous binder and the biocidal compound, the surface-coating compositions may contain various auxiliary materials, such as pigments, extenders, solvents, dyes, defoaming agents, driers, thickcners, emulsifiers, plasticizers, and the like in the amounts ordinarily used for these purposes.

The biocidal compounds may be incorporated into the surface-coating compositions by any convenient procedure. For example, they can be combined with the pigments and other components to form a pigment phase that is mixed with the resinous binder and water or organic solvent to form the surface-coating composition. Alternatively, they can be added to a composition that contains the resinous binder, pigment, and water or organic solvent. The biocidal compounds can be added as such to the other components, or they can be added as a solution in, for example, an alcohol, ether, or ketone.

The invention is further illustrated by the examples that follow:

EXAMPLE 1 A mixture of l7.7 grams (0.l5 mole) of benzimidazole, 6.85 grams (0.228 mole) of paraformaldehyde, l ml. of 5% aqueous sodium hydroxide solution, and 125 ml. of isopropanol was heated at its reflux temperature for minutes and then cooled in an ice bath. The solid product was separated from the reaction mixture by filtration and dried under vacuum at 60C. There was obtained l7.7 grams (80% yield) of l-hydroxymethylbenzimidazole, which melted at l39-l43C. (literature, l39-l4lC.).

EXAMPLE 2 A mixture of 27.0 grams (0.2 mole) of 2-methylbenzimidazole, 9.0 grams (0.3 mole) of paraformaldehyde, 0.5 ml. of 5% aqueous sodium hydroxide solution, and 250 ml. of isopropanol was heated at its reflux temperature for 1.5 hours, cooled to room temperature, and diluted with l50 ml. of isopropanol. The solid product was separated from the reaction mixture by filtration. washed twice with ice-cold isopropanol and once with 4 ice-water. and then dried under vacuum at 60C. 'l here was obtained 17.0 grams (52.3"? yield) of l-hydroxymethyl-2-methylbenzimidazole. which melted at l42.5-l48C.

EXAMPLE 3 A mixture of 24.5 grams (0.l5 mole) of 6-nitrobenzimidazole, 6.85 grams (0.228 mole) of parat'ormaldehyde. 1 ml. of 5% aqueous sodium hydroxide solution. and ml. of isopropanol was heated at its reflux temperature for one hour, cooled in an icebath. and filtered. The product was washed with isopropanol and dried under vacuum at 60C. There was obtained 28.9 grams (lO0% yield) of l-hydroxymethyl-o-nitrobenzimidazole, which melted at l89202C. (literature. 197C.)

EXAMPLE 4 A mixture of 25 grams (0.15 mole) of 2-methyl-5- chlorobenzimidazole, 6.75 grams (0.15 mole) of paraformaldehyde. 0.2 ml. ofa 5% aqueous sodium hydroxide solution, and ISO ml. of isopropanol was heated at its reflux temperature for 2 hours. The mixture was cooled to room temperature, stirred with 5 grams of activated carbon and 2.5 grams of filter-aid, and iii tered. The product was washed with cold isopropanol and dried under vacuum at 50C. There was obtained 13.4 grams (45.5% yield) of l-hydroxymethyl-Z-methyl-S-chlorobenzimidazole, which melted at l59l65C. The product contained 56.99% C, 4.67% H, and [4.68% N (calculated, 55.1% C, 4.58% H, and l4.25% N).

EXAMPLE 5 A mixture of 29.6 grams (0.2 mole) of 2-benzimidazolemethanol, 9.0 grams (0.3 mole) of paraformaldehyde, 0.2 ml. ofa 5% aqueous sodium hydroxide solution, and ml. of isopropanol was heated at its reflux temperature for 30 minutes. The mixture was heated to 80C. under vacuum to remove the solvent. The residue (36.6 grams) was dissolved in 50 ml. of hot isopropanol, and the resulting solution was diluted with about 200 ml. of benzene. The solid that precipitated was separated from the solution and dried. There was obtained 26.8 grams (50.2% yield) of l,2-bis-(hydroxymethyl)benzimidazole, which melted at l09-l l0C. and which contained 61.9% C, 6.0l 7( H, and l6.l 7% N (calculated, 60.7% C, 5.62% H, and [5.7% N).

EXAMPLE 6 A mixture of 22.5 grams (0.l5 mole) of 2-mercaptobenzimidazole, 60 ml. (0.75 mole) ofa 37% aqueous formaldehyde solution, and 200 ml. of water was stirred at room temperature for 24 hours. An additional 50 ml. of water was added, and the reaction mixture was stirred for one hour and then filtered. The product was washed with water and dried under vacuum at 4550C. There was obtained 29.2 grams (92.5% yield) of l-hydroxymethyl-2-hydroxymethylthiobenzimidazole, which melted at l42-l48C. and which contained 52.08% C. 4.59% H. and I390?! N (calcu lated, 5l.4% C, 4.77% H, and 13.33% N).

EXAMPLE 7 A. A polyvinyl acetate emulsion paint was prepared by mixing together the following materials:

Parts by Weight Water 48 l 5 1*"? Aqueous solution ol sodium salt oi Z4 malcic anliydriilei'diisohulylenc copolymer Potassium pyrophosphate 3 Long chain l'atty acid alkanolamidc 9 [)cl'oamer b Ethylene glycol 75 l-li -l' i Aqueous solution ol hydroxy- 375 etliylcellulose Aqueous emulsion containing 55' of i299 polyvinyl acetate Diethyl ether ol dicthylenc glycol Titanium dioxide 690 Talc 345 Calclum metasilicate I50 This paint had the following properties as determined by standard paint test procedures:

Viscosity o5 K.U Brookficltl Viscosity KOI) (.ps tNo. 4 Spindle. fill rpm) pH 7.8 Yellowness Index 3.1)

B. An acrylic latex paint was prepared by mixing together the following materials:

malelc anhydride/diisohutylcne copolymer Detoamcr l2 2% Aqueous solution ol hydroxyethylccllulosc 300 Ethylene glycol 60 Titanium dioxide 750 Mica (waterground) 90 Calcium carbonate 37S Ammonium hydroxide (280?) 6 Aqueous dispersion containing 46% acrylic I642 ester copolymer ma /v ethyl acrylatev 32.5% methyl acrylate. and l.S'/( acrylic acid) This paint had the following properties;

6 C. An exterior house paint was prepared by mixing together the following materials:

Parts by Weight Basic lead carbonate 288 Zinc oxide 232 Titanium dioxide (rutile) I49 Talc Z60 Linseed oil 142 Bodied linseed oil l 14 Mineral spirits l I4 Antiskinning agcnt tExkin 2) 2 Manganese naphthenate (6%) 2.27 Lead naphthenate [249! t l 1.3

EXAMPLE 8 Small amounts of the biocidal compounds of Examples l to 6 were added to portions of the paints whose preparation is described in Example 7. and the treated paints were evaluated by means of an agar diffusion assay. ln this test agar is inoculated with the test organism, the treated paint is placed in a well cut from the agar, and after incubation at 28C. and 85-95% relative humidity, the activity of the biocide is measured by zones of inhibition. The bioeidal compounds tested, the amounts of each that were used. and the results obtained are given in Table I. In this table ZO Zone of inhibition in mm.

0 No zone of inhibition; no growth Tr Trace zone of inhibition Not tested Bacteria A v Mixed paint spoilage strains B Pseudomonas aeruginosa C Aerobacter aerogenes Fungi l Pullularia pullulans 2 Penicillium crustosum 3 Aspergillus niger EXAMPLE 9 Small amounts of the biocidal compounds of this invention were added to portions of the paints whose preparation is described in Example 7, and the treated paints were evaluated by the following procedure:

A mixed bacterial inoculum was prepared by incubation of inoculated (0.5 ml.) mild dilution bottles eonifi Swim, taming ml. of sohdified Trypticase-Soy Agar. (No. 3 Spindle.6(l rpm] After incubation for 18 to 24 hours at 35C., the Q cultures were removed from the agar surface. diluted to e owness Index 2.6 I

an appropriate Table l Activity of N-Hydroxymethylhemimidaloles as Biocides in Paints Test Bioeidal Activity Level FlTect on Liquid Paint Bacteria Fungi Biocidc Paint IV? D pH Odor Color Viscosity A B C l 2 l-Hytlroxyniethyl- PVA Z 71) Slight None None 20-10 20-3 20-3 ZO-X 20-9 ZO-3 hcnximidalole Acrylic 2 7.1 Gelled 20-9 ZO-S 20-5 20-5 ZO-b 20-3 1 7.9 None None 20- Tr Tr l) ZO-l Tr 0.5 3.8 ZO-l Tr U (I l) 0 U25 9.ll l) U U U l) 0 Oil 2 Tr ZO-l Tr lHydroxymcthyl-2- PVA 2 7.1) None None None 20- l (1 20-8 20-9 20-9 7.0-7 Tr lncthylbcnyimidamlc l 7." 20-9 20-8 20-5 Tr Tr Tr [L5 b9 10-7 20-5 7.0-3 I] ll 0 [LI 7,2 Tr Tr Tr U (I (1 Acrylic I 8.0 ZU-K 2.0-7 ZO-ll ZO-ti ZO-lll Tr l 8.] ZO-7 7.0-8 ZO-S Tr Tr Tr 0.5 1-4.4 Tr ZO-S 2.0-3 0 o u ().l 8.5 l] O (1 O U 0 Oil 2 0 Tr Tr l i) O l Hydroxymethyl-Z- PVA 2 LI None Beige None 7.0-7 20-5 207 ZO-l 20-3 Tr mclhyl-i-chloro- Acrylic I 7.4 (jclled ZO-7 ZO-l ZO-3 ZO-J ZO-fi Tr licnlinnda/ole Oil 2 None O (1 t) Table l-continucd Activity ol N-Hydroxymcth lben/imidamles as Biocides in Paints Test liiucitlal Acllvity Level El'l'cct on Liquid Paint Bacteria l ungi Biocidc Paint ("fr pH OLlOI Color Viscosity A B l I 3 l-Hydroxymcthyl-b- PVA 2 7. l None None None 20- l l) 7.0-3 7.( )-5 Tr 7f) lr nitrohcn1imida7ole Acrylic Z R ZO-5 20-3 Tr (I it 1) Oil 2 (I it I) l .Z-Bis( hydroxy- PVA 2 7.3 None None None 2.0- l 4 7.0-6 Z R [0-H 7.06 Tr methyl lhcn/.- Acrylic 2 7.5 Gelled 20-8 20-7 [0-6 'l r l'r l r imida'lolc Oil 2 None U H l) l-HydroxymethyL'l- PVA 3 7.l None None (iellcd ZO l 5 6 ZOJ 7.0-1!) /.()-5 'l r hydroxymcthylthiol 7.3 None ZO- l (l 7.0-7 Z()-5 ZO-(w 7.(J-l 'l r bcnlimidalole 0.5 7.3 7.0-5 ZO-3 Z04 7.0 1 7.0 I Tr l 7.3 ZO-I ZO-l Tr U l) H Acrylic 2 6.5 Gellcd Z04 Z03 Z()-7 7.0-3 20-4 Tr l 7.4 2.0-5 Tr [O l 7.0-: Tr ll 0.. 8.2 ZO-l (I (I i) I) ll ().l 8.5 None 0 (I ll I) ll Oil 1 i l) I) il l A l) I) (I ll.5 A i (l l) (I ().l 1) [I (l Bisl phenylmercury PVA 2 7.0 None None None ZO-7 l) 7.0- 2 20- ll) ZO-ll dodecenylsuccinate Acrylic 2 8.5 20- l 2 20-8 207 [(I I (I 7.04 /.()-l 7 (Super ALHI) Oil 2 i 7.0 Z02 [(111 None PVA 7.2 None None None (I (J t) I) (I ll Acrylic 8 8 (l l) U (I (l Oil ll (1 (l volume in phosphate buffer (0.05 M, pH 7.0). and inoculated into 300 gram portions of the test paints. The amount of the culture added to the paint was such C. with a Brookfield viscometer Model RVM using a N0. 4 spindle at 20 rpm. The percentage decrease of the viscosity of each of the treated paints during the that the final level of bacteria was between 0.5 X IO incubation period is reported in Table ll. and 3 X l0 per gram of paint. After thorou h mixin the paints were incubated at C. under percei t EXAMPLE relative humidity. At intervals during the incubation, Several of the paints whose preparation is described measurements of viability of the bacteria and viscosity in Example 8 were applied to cedar panels that were of the paint were made. The viability test was carried 35 then exposed on test fences. The panels were inspected out by adding an aliquot of the paint to Trypticase-Soy periodically to determine the amount of mildew on the Broth containing lecithin and Tween 80, incubating for paint films. The paints tested and the results obtained 48 hours at 35C.. and then streaking the broth on a are given in Table lll. ln this table, indicates no mil- Trypticase-Soy Agar plate. After a 24 hour incubation dew; 2, slight amount of mildew; 4, slight to moderate period at 35"C. the plates were examined for growth amount of mildew; 6. moderate amount oi mildew; 8 along the streak. The results obtained are reported in moderate to large amount of mildew; and It), large Table ll (growth present) or (growth absent). amount of mildew, The viscosity of the paint samples was measured at Table ll Nllytlroxymethylhen/imida/oles as Paint Preservatives 7v Viscosity Change Viability Test Level 9? Incubation Period Incubation Perlod based on (days! inlays] Biocidc Paint wt. of paint Culture 7 [4 ll l I .1 7 9 l4 2] l-Hydroxymcthyli- PVA 0.25 K 2 ,9 l) (l A W W 7 methylhcnzimidazole 0.40 l 1.9 0 ll) 7 W t l) l ll 0 U K 6.1 7.3 M

Acrylic 0.6" l ll (1 i i v i 77 0.41) l 0 (I n i A l) l 8,7 2.9 3.8

l.Z-Bislhydroxymethyll- PVA 0.25 K 0 (l (I e w 1 benzimidazole 0.4!) l l] (I (I 0.25 l i) ii (I 1 0 K o n n o l 5 s m Acrylic 0.4!) K (1 I) ll U K 45 an 45 K Mixture til Pscudomonas .icrugiimsa and Acrnbaclcr aurora-nus I Mnturl: of Bacillu ublilis. Haelllus ntcgaterlum. and liaclllm ll\l\L'lllittVllll- Table III Outdoor Exposure Panel Evaluation Months on Location Test Test of Test Level Mildew Fe nce Fence Biocide (Z Paint Rating 6 Puerto Rico lHydroxymcthyl2- l.5 Acrylic l) methylbenzimidazolc Bisl phenylmercuric L5 Acrylic dodecenyl succinate None Acrylic 2 l4 Pensacola. l-Hydroxymethyl 2 Acrylic 2 Florida bcnzimidazole Bis(phenylmercuric)- 2 Acrylic 2 dodccenyl guccinate None Acrylic 6 l7 Piscataway. l-Hydroxymcthyl- 2 PVA 2 New Jersey benzimidazole Bis(phcnylmercuric)- 2 PVA dodecenyl succinate None PVA 6 What is claimed is:

l. A surface-coating composition having improved resistance to attack by fungi and bacteria that comprises (a) a water-insoluble, film-forming, resinous binder selected from the group consisting of oleoresinous binders, synthetic linear addition polymers obtained by the vinyl polymerization of ethylenicallyunsaturated molecules, and mixtures thereof and (b) about 0. l 0 percent to 3 percent, based on the weight of said composition, of a biocidal compound having the structural formula CH OH wherein X represents hydrogen, alkyl of l to 4 carbon atoms, hydroxymethyl, or hydroxymethylthio; Y represents nitro or halogen; and n represents a number in the range of 0 and 2.

2. A surface-coating composition as set forth in claim I wherein the biocidal compound is l-hydroxymethylbenzimidazole,

3. A surface-coating composition as set forth in claim I, wherein the biocidal compound is l-hydroxymethyl- Z-methylbenzimidazole.

4. A surface-coating composition as set forth in claim I wherein the biocidal compound is l-hydroxymethyL o-nitrobenzimidazole.

5. A surface-coating composition as set forth in claim I wherein the biocidal compound is l-hydroxymethyl- Z-methyl-S-chlorobenzimidazole.

6. A surface-coating composition as set forth in claim I wherein the biocidal compound is l 2-bis(hydroxymethyl)benzimidazole.

7. A surface-coating composition as set forth in claim I wherein the biocidal compound is l-hydroxymethyllhydroxymethylthiobenzimidazole.

8. A surface-coating composition as set forth in claim I that comprises an aqueous composition that contains about 10 percent to 60 percent by weight of said waterinsoluble resinous binder.

9. A surface-coating composition as set forth in claim 8 that contains from 0.2 percent to 0.6 percent, based on the weight of the composition, of said biocidal compound.

10. The method of controlling the growth of fungi and bacteria in a surface-coating composition that contains a water-insoluble, film-forming, resinous binder selected from the group consisting of oleoresinous binders, synthetic linear addition polymers obtained by the vinyl polymerization of monoethylenicallyunsaturated molecules, and mixtures thereof, which comprises incorporating in said composition about 0J0 percent to 3 percent, based on the weight of said composition, of a biocidal compound having the structural formula o wherein X represents hydrogen, alkyl of l to 4 carbon atoms, hydroxymethyl, or hydroxymethylthio; Y represents nitro or halogen; and n represents a number in the range of 0 to 2.

II. The method of preventing bacteria-caused spoilage in an aqueous surface-coating composition that comprises incorporating in said aqueous composition 0.1 percent to 3 percent, based on the weight of the composition, of a biocidal compound having the structural formula ca on wherein X represents hydrogen, alkyl of l to 4 carbon atoms, hydroxymethyl, or hydroxymethylthio; Y reprel l scnts nitro or halogen; and n represents a number in the range of O to 2.

12. The method f claim 11 wherein 0.2 percent to 0.6 percent by weight of the biocidal compound is incorporated into the aqueous surfuce-cnuting composition. 

1. A SURFACE-COATING COMPOSITION HAVING IMPROVED RESISTANCE TO ATTACK BY FUNGI AND BACTERIA THAT COMPRISES (A) A WATER-SOLUBLE, FILM-FORMING, RESINOUS BINDER SYNTHETIC LINEAR THE GROUP CONSISTING OF OLEORESINOUS BINDERS, SYNTHETIC LINEAR ADDITION POLYMERS OBTAINED BY THE VINYL POLYMERIZATION OF ETHYLENICALLY-UNSATURATED MOLECULES, AND MIXTURES THEREOF (B) ABOUT 0.10 PERCENT TO 3 PERCENT, BASED ON THE WEIGHT OF SAID COMPOSITION, OF A BIOCIDAL COMPOUNDS HAVING THE STRUCTURAL FORMULA
 2. A surface-coating composition as set forth in claim 1 wherein the biocidal compound is 1-hydroxymethylbenzimidazole.
 3. A surface-coating composition as set forth in claim 1, wherein the biocidal compound is 1-hydroxymethyl-2-methylbenzimidazole.
 4. A surface-coating composition as set forth in claim 1 wherein the biocidal compound is 1-hydroxymethyl-6-nitrobenzimidazolE.
 5. A surface-coating composition as set forth in claim 1 wherein the biocidal compound is 1-hydroxymethyl-2-methyl-5-chlorobenzimidazole.
 6. A surface-coating composition as set forth in claim 1 wherein the biocidal compound is 1,2-bis(hydroxymethyl)benzimidazole.
 7. A surface-coating composition as set forth in claim 1 wherein the biocidal compound is 1-hydroxymethyl-2-hydroxymethylthiobenzimidazole.
 8. A surface-coating composition as set forth in claim 1 that comprises an aqueous composition that contains about 10 percent to 60 percent by weight of said water-insoluble resinous binder.
 9. A surface-coating composition as set forth in claim 8 that contains from 0.2 percent to 0.6 percent, based on the weight of the composition, of said biocidal compound.
 10. The method of controlling the growth of fungi and bacteria in a surface-coating composition that contains a water-insoluble, film-forming, resinous binder selected from the group consisting of oleoresinous binders, synthetic linear addition polymers obtained by the vinyl polymerization of monoethylenically-unsaturated molecules, and mixtures thereof, which comprises incorporating in said composition about 0.10 percent to 3 percent, based on the weight of said composition, of a biocidal compound having the structural formula
 11. The method of preventing bacteria-caused spoilage in an aqueous surface-coating composition that comprises incorporating in said aqueous composition 0.1 percent to 3 percent, based on the weight of the composition, of a biocidal compound having the structural formula
 12. The method of claim 11 wherein 0.2 percent to 0.6 percent by weight of the biocidal compound is incorporated into the aqueous surface-coating composition. 